Lock.



G. N. MASON.

LOOK.

APPLIOATION FILED AUG. 31, 1911.

Patented Aug. 20, 1912.

figm- 5 Iflla son, Snow/144207, I

I v a I aflomau COLUMBIA PLANDGRAPH co., WASHINGTON, n c.

UNITED STATES PATENT OFFICE.

GEORGE N. MASON, OF READING, PENNSYLVANIA, ASSIGNOR TO READING HARDWARE COMPANY, OF READING, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

LOCK.

Specification of Letters Patent.

Application filed August 31, 1911.

Serial No. 646,978.

To all whom it may concern Be it known that I, GEORGE N. MASON, citizen of the United States, residing at Reading, in the county of Berks and State of Pennsylvania, have invented certain new and useful Improvements in Locks, of which the following is a specification.

This invention relates to improvements in door locks and the object in the present in.- stance is to provide a lock for use on doors of communicating rooms, Where it is desirable to lock the door from either side by independent locking bolts, so that it cannot be unlocked from the other side.

The particular intention in the present construction is to provide means, in the form of independent key operated mechanism, for locking the door so that it cannot be opened from either side, even though both of the usual independent locking means are operated to retract both the locking bolts.

The invention consists of a dead locking slide, operated from one side of the door only, whereby the latch bolt may be dead locked in protracted position, so that even though the locking bolts are unlocked, the latch bolt cannot be retracted.

The invention is more fully described in the following specification and clearly illustrated in the accompanying drawing, in which Figure 1 is a side elevation of my lock with the casing plate removed and showing the latch bolt in dead locked position. Fig. 2 is a partial view of the lock, showing the latch bolt protracted, but with the dead locking slide out of engagement therewith. Fig. 3 is a sectional view on line 33 of Fig. 2.

The numeral 1 designates the lock casing; 2 and 3 the usual independent locking bolts and 4 the two part hub by means of which the locking bolts are moved.

5 designates the latch bolt, and this is formed with a shoulder 6 at its lower side adapted to be engaged by the dead locking slide 8. This slide is located in the casing below the latch, and is provided with a'set of tumblers 7 and capable of being operated by means of a key inserted in one side of the casing only.

When it is desired to dead lock the latch bolt, the slide is protracted by turning the key, which will throw the slide to forward position, as in Fig. 1, when it will abut a ainst the shoulder 6 of the latch bolt and e ectually prevent its retraction. In this manner, even when both of the independent locking bolts are retracted, it will be impossible to open the door, when locked by the dead locking slide, inasmuch as the movement of the door knob, through its connection with the latch bolt, is arrested.

Having thus described my invention, what I claim and desire to secure by Letters Patent is 1. The. combination, in a door lock, of a casing, a pair of independent locking bolts each of which is operable from one side of the door only, a latch bolt, means for operating the same, a dead locking slide movable to engage and hold said latch bolt protracted, and key controlled means operable from one side of the door only for actuating said slide.

2. The combination, in a door lock, of a pair of independent locking bolts each of which is operable from one side of the door only, a latch bolt, means for operating the same, a dead locking slide movable to engage and hold said latch bolt protracted, and a set of key-controlled tumblers carried by the slide and operable from one side of the door only, whereby said slide may be protracted and retracted.

3. In a door lock the combination of a casing, two independent locking bolts each of which is operable from one side of the door only, inside and outside thumb pieces, a two-part hub each part of which is independently operable by one of said thumb pieces for moving the locking bolts, a latch bolt formed with a shoulder on its under side in close proximity to its forward end, an independent, key'operated, horizontally movable dead locking slide capable of being operated from one side of the door only and adapted to abut against said shoulder when the latch bolt is in projected position and a set of key actuated tumblers carried by said slide.

In testimony whereof I aflix my signature in presence of two witnesses.

GEORGE N. MASON.

Witnesses:

ED. A. KELLY, CLARA E. YOUNG.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0.

Patented Aug. 20, 1912. 

